The present invention relates to detergent particles having high-speed dissolubility and a method for preparing the same, and a detergent composition comprising the detergent particles.
Recently, in order to meet the consumers"" need xe2x80x9cto speedily finish laundry,xe2x80x9d the commercially available washing machines have the tendency of having large volumes, i.e. large amounts of laundry can be done at one time, and there is a mode of a short washing cycle for the washing time. In addition, in order to meet the consumers"" need xe2x80x9cto carefully wash the clothes,xe2x80x9d a gentle stirring cycle is arranged, thereby making it possible to reduce the clothes damaging. In addition, in order to meet environmental problems and energy-saving problems and have economic advantages, there are the trends for saving water, low-temperature washing and shortening of operation time.
All of these trends lead to decrease in the amount of work, which is a product of mechanical power and period of time, of the washing machines. As a result, the detergency is deteriorated owing to a decrease in the dissolution rate of the detergent particle, and the remaining insolubles of powdery detergents and the detergent particle remaining on clothes are increased at completion of washing cycle.
As a prior art in an attempt to solve these matters, Japanese Patent Laid-Open No. 5-247497 discloses a method of preparing a detergent composition having a high dissolubility, comprising, during the preparation of a crutcher slurry including zeolite, adding a citrate and spray-drying the mixture to obtain beads with improved strength, and applying a surfactant on the beads.
In addition, Japanese Unexamined Patent Publication No. 3-504734 discloses a granular adsorbent including 45 to 75% by weight of zeolite, 1 to 6% by weight of a soap, 1 to 12% by weight of a polymer, 0 to 25% by weight of sodium sulfate, 0 to 5% by weight of a nonionic surfactant, and 10 to 24% by weight of water, and supporting a surfactant by its high adsorption ability, wherein the granular adsorbent by which the surfactant is supported has a good distributive behavior into the washing machine.
However, in these publications, the above technological problems cannot be sufficiently solved, and in particular, these publications do not disclose a technology intending to prepare detergents which can dissolve at high speeds.
Therefore, as to typical powdery detergents which have been made commercially available, their dissolution rates after 60 seconds and 30 seconds supplying the powder detergent to water at 5xc2x0 C. as defined in the present invention is measured by the method set forth in the present specification. As result, the dissolution rates after 60 seconds for detergents made commercially available in Japan, typical nine compact-type detergents, are in the range from 64 to 87%; the dissolution rates for detergents made commercially available in the U.S., typical four compact-type detergents, are in the range from 75 to 88%; the dissolution rates for detergents made commercially available in Europe, typical three compact-type detergents, are in the range from 57 to 70%; and the dissolution rates for detergents made commercially available in Asia and Oceania, typical two compact-type detergents, are in the range from 64 to 69%. And the dissolution rates after 30 seconds for detergents made commercially available in Japan, typical nine compact-type detergents, are in the range from 55 to 73%; the dissolution rates for detergents made commercially available in the U.S., typical four compact-type detergents, are in the range from 65 to 81%; the dissolution rates for detergents made commercially available in Europe, typical three compact-type detergents, are in the range from 40 to 60%; and the dissolution rates for detergents made commercially available in Asia and Oceania, typical two compact-type detergents, are in the range from 55 to 60%. The extent of the dissolution rates obtained above cannot be said to sufficiently meet the trends for demands in low-mechanical power mentioned above.
Accordingly, in order to meet the above problems, an object of the present invention is to provide detergent particles having high-speed dissolubility capable of dissolving quickly in water after supplying the detergent particles in water, and a method for preparing the detergent particles, and a detergent composition comprising the detergent particles.
The present invention pertains to the following:
[1] detergent particles having an average particle size of from 150 to 500 xcexcm and a bulk density of 500 g/liter or more, wherein the detergent particles comprising a detergent particle being capable of releasing a bubble from an inner portion of the detergent particle in a process of dissolving the detergent particle in water, the bubble having a size of one-tenth or more of a particle size of the detergent particle, and wherein the detergent particles have a dissolution rate of 90% or more, under conditions where the detergent particles are supplied in water at 5xc2x0 C.; stirred for 60 seconds under the stirring conditions (hereinafter simply referred to as xe2x80x9ctest stirring conditionsxe2x80x9d) that 1 g of the detergent particles is supplied to a one-liter beaker having an inner diameter of 105 mm which is charged with one-liter of hard water having 71.2 mg CaCO3/liter, wherein a molar ratio of Ca/Mg is 7/3, and stirred with a stirring bar of 35 mm in length and 8 mm in diameter at a rotational speed of 800 rpm; and filtered with a standard sieve having a sieve-opening of 74 xcexcm as defined by JIS Z 8801, wherein the dissolution rate is calculated by Equation (1):
Dissolution Rate (%)=[1xe2x88x92(T/S)]xc3x97100xe2x80x83xe2x80x83(1)
wherein S is a weight (g) of the detergent particles supplied; and T is a dry weight (g) of remaining insolubles of the detergent particles remaining on the sieve when a liquid prepared under the test stirring conditions is filtered with the sieve, wherein drying conditions for the remaining insolubles are keeping at a temperature of 105xc2x0 C. for 1 hour, and then in a desiccator with a silica gel at 25xc2x0 C. for 30 minutes, or wherein the detergent particles have a dissolution rate of 82% or more, as similarly calculated with stirring for 30 seconds;
[2] detergent particles having an average particle size of from 150 to 500 xcexcm and a bulk density of 500 g/liter or more, wherein the detergent particles are a collective of a detergent particle comprising a base particle comprising a water-insoluble inorganic compound, a water-soluble polymer and a water-soluble salt, and a surfactant supported by the base particle, wherein the base particle has a localized structure in which larger portions of the water-soluble polymer and the water-soluble salt are present near the surface of the base particle rather than in the inner portion thereof, and wherein the detergent particles have a dissolution rate as calculated by Equation (1) of 90% or more, under conditions where the detergent particles are supplied in water at 5xc2x0 C.; stirred for 60 seconds under the test stirring conditions; and filtered with a standard sieve having a sieve-opening of 74 xcexcm as defined by JIS Z 8801, or wherein the detergent particles have a dissolution rate of 82% or more, as similarly calculated with stirring for 30 seconds;
[3] a method for preparing the detergent particles as defined in item [1] or item [2] above, comprising the steps of:
Step (a): preparing a slurry containing a water-insoluble inorganic compound, a water-soluble polymer, and a water-soluble salt, wherein 60% by weight or more of water-soluble components including the water-soluble polymer and the water-soluble salt is dissolved in the slurry;
Step (b): spray-drying the slurry obtained in Step (a) to prepare base particles; and
Step (c): adding a surfactant to the base particles obtained in Step (b) to support the surfactant thereby;
[4] a detergent composition comprising the detergent particles as defined in item [1] or item [2] above in an amount of 50% by weight or more; and
[5] a detergent composition having an average particle size of from 150 to 500 xcexcm and a bulk density of 500 g/liter or more, wherein the detergent composition comprising a detergent particle being capable of releasing a bubble from an inner portion of the detergent particle in a process of dissolving the detergent particle in water, the bubble having a size of one-tenth or more of a particle size of the detergent particle, and wherein the detergent composition has a dissolution rate as calculated by Equation (1) of 90% or more, under conditions where the detergent composition is supplied in water at 5xc2x0 C.; stirred for 60 seconds under the test stirring conditions; and filtered with a standard sieve having a sieve-opening of 74 xcexcm as defined by JIS Z 8801, or wherein the detergent composition has a dissolution rate of 82% or more, as similarly calculated with stirring for 30 seconds.